We are currently in the midst of a genetics revolution that promises to push "breakthrough" biomedical research to new levels. A large part of this revolution depends upon the analysis of the relationships between genes and their effects on complex biological systems and phenotypes. Investigators must become increasingly skilled in the use of mathematical, computational and statistical tools to address a variety of important biological questions. Similarly, scientists with mathematical or computational backgrounds who wish to apply their skills to some of these complex problems will need to develop a deeper understanding of the biological principles involved. Therefore, this course highlights current approaches used to address the analysis of complex genetic traits both in humans and other model systems, and is designed for biologists requiring training in the use of mathematical, computational and statistical tools as well for scientists with mathematical or computational backgrounds that wish to develop a deeper understanding of contemporary biological problems in genetics. The overall goal of this course is to train new scientists and re-train established investigators in the use of mathematical tools for the analysis of complex phenotypes and systems. Those completing the course will acquire a critical working knowledge of experimental approaches to: (1) mapping genes in inbred lines, (2) lineage analysis and mapping genes in pedigrees, 3) association analysis and mapping genes in populations, and (4) bio-informatics and software tools for database "mining". These aims will be accomplished by offering an intensive 7-day course to 30 participants chosen for their outstanding research potential. Participants will interact with a group of prominent computational biologists, bio- informaticists, biologists and geneticists both from The Jackson Laboratory and other institutions. Student enrollment is kept deliberately small to achieve a desirable level of student-faculty interaction. Didactic sessions will be held in the mornings, while the afternoon and evening sessions will be reserved for hands-on training workshops and case by case examples of on-going projects in complex trait analysis.